The influence of litter birth weight phenotype on embryonic and placental development at day 30 of gestation in multiparous purebred Large White sows.

The aim of this study was to understand the intrauterine biological processes associated with the low litter birth weight phenotype in pigs. Analyses were conducted on reproductive data from a purebred Large White maternal line to identify sows (>2 parities) with repeatable high or low litter birth weight phenotype (HLBWP or LLBWP). A total of 40 sows were selected (n = 20 HLBWP and n = 20 LLBWP) and bred with semen from purebred Large White boars of proven fertility. Sows were euthanized on day 28-30 of gestation (day 29.5 ± 0.6) and samples of placenta and embryos collected. Total number of embryos (TNE), embryonic weight (EW), embryonic viability, and crown-rump (CRL) measurements were recorded, along with the ovulation rate (OR) and allantochorionic fluid volume (AFV). No significant difference was detected (P > 0.05) in OR, TNE, and number of viable embryos on day 30 of gestation between the two groups. There was no significant difference in EW (LLBWP: 0.80 ± 0.05 g; HLBWP: 0.88 ± 0.04 g, P = 0.18) or CRL (LLBWP: 21.5 ± 0.7 mm; HLBWP: 21.9 ± 0.68 mm, P = 0.46). Placental development represented by the average AFV was significantly lower in the LLBWP compared to HLBWP (LLBWP: 131 ± 9.82 mL; HLBWP: 149 ± 9.39 mL, P = 0.03). In conclusion, placental development may be the main factor causing lower BW of entire litters in LLBWP sows.

Energy and protein dilution in broiler breeder pullet diets reduced offspring body weight and yield.

The objective of the current research was to evaluate transgenerational effects of maternal dietary energy and protein on growth, efficiency, and yield of broiler offspring. A factorial arrangement of treatments consisting of high and low ME and CP levels fed during the rearing and laying phases was used. The study was a final 2 × 2 × 2 × 2 factorial arrangement of treatments, including broiler sex. Ross 708 broiler breeder pullets (n = 933) were fed diets containing 2,736 (HEREAR) or 2,528 kcal/kg ME (LEREAR) with either 15.3% (HPREAR) or 13.7% CP (LPREAR). From 25 wk, dams were fed a 15% CP laying diet containing 2,900 (HELAY) or 2,800 kcal/kg ME (LELAY). Following artificial insemination of the dams at 35 wk, eggs were collected for 1 wk, incubated, and pedigree hatched to preserve maternal identity. Broiler offspring were placed sex-separately into 32 pens, according to laying phase maternal treatments, with rearing maternal treatments nested within pens. Individual BW and pen level feed intake were recorded weekly. Broilers were processed at 40 d of age to evaluate yield. Maternal diet effects on offspring BW were sex dependent and transient. Female LPREAR × LELAY broilers had lower pectoralis major and carcass yield than HPREAR × LELAY females. Male HPREAR × HELAY broilers had increased breast yield (19.8%) compared with 18.4% in HPREAR × LELAY broilers. Carcass yield was lower in LEREAR × HPREAR broilers (63.7%) compared with HEREAR × HPREAR broilers (64.9%). LEREAR × HPREAR dams had the lowest ME to CP ratio (E: P) diets and highest rearing phase CP intake. Maternal diet did not influence offspring FCR. The most consistent contributor to increased BW was higher maternal dietary CP and ME during rearing. Low ME maternal laying phase diets increased BW of male offspring more consistently than of female offspring. Maternal nutrition also influenced broiler yield, and is thus economically important. Energy and protein dilution in broiler breeder pullet diets may have detrimental effects on offspring performance.

Precision feeding: Innovative management of broiler breeder feed intake and flock uniformity.

Achieving high lifetime productivity with broiler breeder flocks is challenging because feed restriction intensity continues to increase due to selection for efficient, fast growing, and high yielding broilers. Flock uniformity is compromised by intense competition for limited feed. Equitable feed allocation and stable metabolic rates are likely to increase reproductive efficiency. A prototype precision feeding (PF) station was developed to sequentially feed birds according to their individual needs. If pullets were under target BW, the station provided small amounts of feed during short feeding bouts. The objectives of the current study were to determine whether a sequential PF system could control BW of individual group-housed pullets by matching real-time BW to BW targets, and to quantify fluctuations in metabolic rate using continuous or stepwise increases in target BW. Two treatments were used in a completely randomized design: CON, the Ross 708 target BW curve interpolated hourly; and STEP, the Ross 708 BW curve updated every 21 days. Twenty Ross 708 broiler breeder pullets were assigned to the treatments (n = 10 per treatment). All pullets were fed by one PF station in a single pen from 35 to 140 d of age. Feed intake and BW records were used to evaluate BW and BW variation to estimate maintenance ME requirements, and to evaluate feeding patterns. Differences were reported as significant where P < 0.05. Precision feeding allowed different feeding programs to be evaluated in the same pen. In both treatments, BW CV decreased to less than 2% by wk 20. Complex temporal differences in feed intake and BW reflected treatment-specific target growth trajectories. Metabolic rate in the STEP treatment increased 70 to 100% during wk in which rapid growth was permitted, compared with wk in which BW targets were held constant. Precision feeding shows promise both as a data acquisition system for poultry researchers and breeders, and as a means of increasing broiler breeder flock uniformity.

Effects of environmental temperature and dietary energy on energy partitioning coefficients of female broiler breeders.

With increasing disparity between broiler breeder target weights and broiler growth potential, maintenance energy requirements have become a larger proportion of total broiler breeder energy intake. Because energy is partitioned to growth and egg production at a lower priority than maintenance, accurate prediction of maintenance energy requirements is important for practical broiler breeder feed allocation decisions. Environmental temperature affects the maintenance energy requirement by changing rate of heat loss to the environment. In the ME system, heat production (energy lost) is part of the maintenance requirement (ME). In the current study, a nonlinear mixed model was derived to predict ME partitioning of broiler breeder hens under varied temperature conditions. At 21 wk of age, 192 Ross 708 hens were individually caged within 6 controlled environmental chambers. From 25 to 41 wk, 4 temperature treatments (15°C, 19°C, 23°C, and 27°C) were randomly assigned to the chambers for 2-week periods. Half of the birds in each chamber were fed a high-energy (HE; 2,912 kcal/kg) diet, and half were fed a low-energy (LE; 2,790 kcal/kg) diet. The nonlinear mixed regression model included a normally distributed random term representing individual hen maintenance, a quadratic response to environmental temperature, and linear ADG and egg mass (EM) coefficients. The model assumed that energy requirements for BW gain and egg production were not influenced by environmental temperature because hens were homeothermic, and the cellular processes for associated biochemical processes occurred within a controlled narrow core body temperature range. Residual feed intake (RFI) and residual ME (RME) were used to estimate efficiency. A quadratic effect of environmental temperature on broiler breeder MEm was predicted ( < 0.0001), with a minimum energy expenditure at 24.3°C. Predicted ME at 21°C was 92.5 kcal/kg; requirements for gain and EM were 2.126 and 1.789 kcal/g, respectively ( < 0.0001). Birds fed the HE diet were more efficient, with a lower RME than birds on the LE diet (-0.63 vs. 0.63 kcal/kg), translating to ME of 135.2 and 136.5 kcal/kg, respectively. In the current experiment, optimal biological efficiency was predicted at 24.3°C in feed-restricted broiler breeders fed the HE diet.

Effect of maternal dietary energy and protein on live performance and yield dynamics of broiler progeny from young breeders.

The objective of this research was to evaluate effects of female broiler breeder dietary ME and CP during rearing and dietary ME during early lay on broiler offspring performance and carcass yield dynamics. A factorial arrangement of treatments, with 2 ME levels, and 2 balanced protein levels from 3 to 24 wk, followed by 2 ME levels in the lay diets, and in the broilers, 2 sexes. A total of 1,635 broilers were housed in 32 pens, with 8 replicate pens according to maternal laying diet and sex. Maternal pullet diets were nested within pen (n = 9 to 14, depending on hatch rate). The broilers originated from 384 Ross 708 hens, which had been fed diets containing high (2,736 kcal/kg, HEREAR) or low ME (2,528 kcal/kg, LEREAR) combined with either high (15.3%, HPREAR) or low balanced protein (13.7% CP, LPREAR). Equal numbers of hens from each pullet treatment were then fed either a high (2,900 kcal/kg, HELAY) or low ME diet (2,800 kcal/kg, LELAY) containing 15% CP. Broilers were hatched from eggs collected at 28 wk of age, and fed identical diets. Broilers were individually weighed weekly. Serial dissections were conducted to evaluate yield breast muscle and abdominal fatpad dynamics. At 39 d, 180 broilers were processed to measure carcass yield. Female progeny of hens with the lowest CP intake during rearing (HEREAR × LPREAR) were lighter from 22 to 36 d of age than female offspring from hens that consumed more CP as pullets. We predicted the heaviest female progeny would result from an ME:CP ratio of 18.25 kcal/g in maternal pullet diets (P = 0.0063). Broiler breast yield increased when maternal EM:CP ratio increased after switching from pullet to laying diets. Hens fed HEREAR were fatter and had fatter progeny than LEREAR. Maternal diet, even during the pullet phase, influenced progeny growth and yield.

The design and use of the Personal Environmental Sampling Backpack (PESB II) for activity-specific exposure monitoring of career pig barn workers.

Career pig barn workers in large confinement barns are exposed to airborne contaminants that need to be quantified. Monitoring instrumentation had to be sanitized to satisfy the biosecurity entrance requirements for pig barns. We satisfied this requirement with the development of a portable Personal Environmental Sampling Backpack (PESB). A pilot study was conducted with the original PESB after which modifications were made to construct the PESB II. The objective of the present study was to modify the PESB to create a monitoring system that is acceptable to workers, accurate, able to collect and store data reliably, and transferable from one animal confinement operation to another. A CO2 sensor with a higher detection range was incorporated into the new instrumentation, H2S monitoring capability was added, and improvements were made to the amount of data the new PESB II instrumentation could store. Compared to the original PESB, the PESB II has a lower mass and volume (reduced by 46% and 70%, respectively), a wider range of CO2 measurement capability, an H2S sensor, a data logger with more data capacity for 11.5 h of real-time monitoring, and a high level of worker acceptability. Apart from revealing a problem with H2S cross-reacting with the NH3 sensor, the PESB II system measured all other parameters reliably and accurately while allowing disinfection to meet stringent biosecurity protocols.